Amplifier



-citizen of the Patented Nov. 4, 1924.

v'YiroLn A. nacnvicz,

or sYnacUsnnEw Yonx.

AMYLIFIER.

Application med April 26, 1922. Seria1 'No. 556,785.

To all whom t may concern.:

Be it known that I, Yr'rono A.

United States, residing at Syracuse, in the county of Onondaga and State of New York, have invented certain new and useful Improvements in of which the following is a speciication.

Tlhis invention relates to an impulse or movement ampliierand has special reference to a method and means for the amplification oi' resistance variations in an electrical circuit by means of a shifting light beam.

It is a well known act that certain substances, such as selenium and the like vary in electrical conductivity in accordance with the intensity of light falling on them so that when such substances are screened from the BAcnvroz, a

light their conductivity is practicallyzero.

. the other across to provide an imponderable lf two parallel resistance elements are bridged throughout their length by such a substance and are connected in an electric circuitV in such manner that'the current, in order to flow will have to pass from one to the bridge in a U shaped path the effective length o these elements may be regulated by keeping the major part of the bridge darkened and throwing a bar of light across such bridge at the point where itis desired to establish conductivity. Inother words, the light bar will constitute a rictionless and imponderable slider for a parallel resistance rheostat.

The principal object of'this invention is improved method and means for utilizing a light bar as a resistance controlling element.

The application o a beam oi light as an lever arm for the am liflcation of movement is well known in p ysics.

A second important obj ect of the invention is to provide an improved amplifying device suitable for the detection and measurement of delicate or minute movements such as electrical impulses, sound waves and in fact vibration, oscillations and other movements of all sorts which require orthe measurement and detection amplification and which on account of their character are diiiicult of such amplification by ordinary mechanical means.

With the aboveY and other 'obj ects in view, the invention consists in general of certain novel details 'of construction and combina-V tions o parts hereinafter fully described, illustrated in the accompanying drawings, and specifically claimed.'

the accompanying drawings, like Amplifiers,

Y ing the position 4cave so that a narrow bar or beam entering characters of reierence indicate like parts in the several views,and

Figure 1 is a general view of the entire apparatus, the View being in side elevation and partly diagrammatic.

Figure 2 is a. plan view cell or element.

Figure 3 is a section on the line 3--3 o Figure 2. f

This principal part of this invention may be termed aphoto-rheostat and consists of aV pair of bars 10 and 11 atleast one of which constitutes a high resistance element. These bars arranged side by side in parallellsm of* the resistance Y and are separated 4from each other by a thin strip 12 of a suitable insulation such as mica or the like. At one end the pair oi bars are provided with binding at each end a sleeve 14 of insulating material passes through the bars so that a bolt 15 may extend through and nut of said bolt resting oninsulating washers 16. By this means the two bars are held in accurately spaced relation throughout their length.

The bars and insulating strip are curved concentric with a point 17 and the convex side of this structure is entirely covered over by a thin layer 18 of a suitable substance possessing the power of becoming a conductor of electricity when expose .thecoating may consist lenium, one of the thallium compound as thaloide or one of the known sulphides having such property. The coating may be applied by fusion so that it entirely covers this surface and bridges over the insulation between the conductor bars.

With a structure such as this, which is preferably termed the photo-rheostatic cell, supported in the dark and so arranged that a beam of light in the form of aA narrow bar may sweep over itvfrom the point 17 -it' will be obvious that the effective length of the high resistance bars may be varied by shiftof the light spot on surfacev which is photo-conductive. This cellis preferably supported in a dark of sethe conposts 13 and i this sleeve, the head da) light. rm:-

s such Y casing 19 having a narrow slit 20 in one slde I beam of light may enter the casing Jfrom a suitable source of illumination such as the lamp- 21. For the purpose of illustration a mirror 2i? is shown as pivoted at the center 17 so that the vlight the slot 20 strikes the mirror at its axiswith such a construction which is to be understood as merelytypical, it isV obvious that any movement spot on the .if the mirror is moved to in theldotted lines the light' spot will strike ment of the mirrorabout the mirror at its axis will cause movement of the -light instance ifvthe mirror is in the yosition shown diagrammatically in full llnes the light spot will strike the cell at A in this case the effective length, ments, of the bars 10 and l1 will be the measurement along the arc A-B. Again, theV position shown the cell at C and the effective length of said bars will be B-C. As typical of one means for moving the mirrorit may be assumed that a vibratory diaphragm 23 forms part of the receiver of a telephone and is connected to the mirror by a link 24. Under Ithese circumstances it will be obvious that vibration of such diaphragm under the iniiuence of electric impulses or waves, such. as are utilized in the telephone for producingthis vibration, will produce similary oscillation of the mirror and consequently the light spot will iicker back and forth on the cell. If now the binding connected to them and these wires are connected'in series through such an instrument as a telephone then the shifting of the light spot on the photo-conductive surface will cause consequent vari'ations in the resistance in the circuit through the telephone receivers 27 and depending on the radlus of the cell the movemay be amplified to any required degree, it being understood that the intensity of the light spot is mantained irrespective of t e radius of curvature of the cell; oscillations may be indenitely increased over the oscillations in the circuit actuating the diaphragm 23.

desired a measuring instrument such as a milliameter 29 circuit. -V y i Now it is to be understood that while the may be used inthe local cell has been here shown as connected for and eiiicient device of telephonie amplitcations it intended to restrict the device to such use alone, that the mirror 22may be diiierent ceiver 27 or milliameter 29 or both of these may berepla'ced in the local circuit by any suitable measuring or (detecting) energy transforming instrument or apparatus'and that such local circuit may even be used as a means for actuatin the mirror of a second "apparatus of thischaracter so as to prod tion.

There has thus been is by no means application of the since it is obvious actuated by many provided a simple the kind ldescribed and for the purposes specified.' e

It is obvious that minor .changes may be photo-conductive surface. For

as resistance eleposts have wires 25 and 26 receiver 27 and a battery 284 In this manner the local circuit means and also that either the re` uce a multi-stage or cascade amplicainvention without departing from thema terial principles thereof. .It is lnot therefore desired to connethe invention to thev exact form herein shown and described but it is wished to include all .such as properly come within the scope claimed.

'or undisto'rted amplification of 'an impulse the light sensitive substance covering the` resistance bars must be of uniform thicknessas well as resistance throughout. For this latter the resistance bars must be per- .fectly parallel. The resistance bars must be ofl uniform resistance throughout.l

A photo electric. cell may be used in the same capacity as the cell using the light reactive substance, only it would require alterations indesign to suit it to'this kind of work. In this case a rubidium screen or some other -similar material would be used in place of the selenium or light reactivev substance covering the resistance rods.

`Instead ofincreasing the actual distance between cell and point of'reflection to obtain increased motion of the bar of lioht which crosses the resistance bars perpen icularly, a suitable system of unions'may be used, this would also necessitate a suitable alteration in the shape of the cell, i. e., the curvature in relation to the point of reection.

Having thus described the invention, what is claimedl as new, is

l. A resistance element including a pair of spaced arcuate bars having equal radii and arranged side by side with their centers of curvature at common axis, said bars .beingl electrically separated and at least one bar being of high resistance material and a bridge of photo-conductive material extending' from end to end of and bridging the space between. said bars. .s

2. -A resistance element including a. pair ofspaced arcuate bars having'equal radii and arranged side by side with their centers of curvature at common axis, said bars being electrically separated and at least one ar being of high resistance material, a

bridge of photo-conductive material extend# ing from end to end of and bridging the space between said bars, and means at one endtof the element for connection of a pair of circuit wires, each to a respective bar.

3. A resistance element. including a pair ofdspaced arcuate bars having equal radii an 4. A resistance elementincluding a pair of spaced arcuate bars having equal radii and arranged side by side with their centers of curvature at common axis, said bars being electrically separated and at least onel bar being of high resistance material, a bridge of photo-conductive material extending from end to end of and bridging the space between the said-bars, means at the center of curvature of said bars for projecting an oscillatable light beam on the photo-conductive bridge, and means at one end of the element for connection of a pair of circuit wires, each to a respective b ar.

l 5. A resistance elementl including a pair of spaced arcuate bars having equal radii and arranged side by side with their centers of curvature 'at common axis, said bars being electrically separated and at least one bar being of highv resistance material, aA

VYTOLD A. BACEVICZ.

I Witnesses:

HARRY G. Ermorr, WILLARD D. SNYDER.

light beam on the 

